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1.
Mol Psychiatry ; 23(8): 1756-1763, 2018 08.
Article in English | MEDLINE | ID: mdl-29112198

ABSTRACT

A previous genetic study has suggested that schizophrenia, bipolar disorder, major depressive disorder, autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) share common disease-associated genes. However, whether individuals with first-degree relatives (FDRs) with schizophrenia have a higher risk of these major psychiatric disorders requires further investigation. This study used Taiwan's National Health Insurance Research Database and identified 151 650 patients with schizophrenia and 227 967 individuals with FDRs with schizophrenia. The relative risks (RRs) of schizophrenia and other major psychiatric disorders were assessed in individuals with FDRs with schizophrenia. The individuals with FDRs with schizophrenia exhibited higher RRs (95% confidence interval) of major psychiatric disorders, namely schizophrenia (4.76, 4.65-4.88), bipolar disorder (3.23, 3.12-3.35), major depressive disorder (2.05, 2.00-2.10), ASD (2.55, 2.35-2.77) and ADHD (1.31, 1.25-1.37) than were found in the total population. Several sensitivity analyses were conducted to confirm these results. A dose-dependent relationship was observed between the risks of major psychiatric disorders and the numbers of FDRs with schizophrenia. The increased risks of major psychiatric disorders were consistent in different family relationships, namely among parents, offspring, siblings and twins. Our study supports the familial dose-dependent co-aggregation of schizophrenia, bipolar disorder, major depressive disorder, ASD and ADHD, and our results may prompt governmental public health departments and psychiatrists to focus on the mental health of individuals with FDRs with schizophrenia.


Subject(s)
Family , Genetic Predisposition to Disease , Mental Disorders/epidemiology , Mental Disorders/genetics , Adult , Female , Humans , Male , Taiwan
2.
Phys Rev Lett ; 117(23): 236402, 2016 Dec 02.
Article in English | MEDLINE | ID: mdl-27982650

ABSTRACT

The topology of pure Bi is controversial because of its very small (∼10 meV) band gap. Here we perform high-resolution angle-resolved photoelectron spectroscopy measurements systematically on 14-202 bilayer Bi films. Using high-quality films, we succeed in observing quantized bulk bands with energy separations down to ∼10 meV. Detailed analyses on the phase shift of the confined wave functions precisely determine the surface and bulk electronic structures, which unambiguously show nontrivial topology. The present results not only prove the fundamental property of Bi but also introduce a capability of the quantum-confinement approach.

3.
Genet Mol Res ; 15(2)2016 Jul 14.
Article in English | MEDLINE | ID: mdl-27421022

ABSTRACT

Genome-wide association studies have identified a single nucleotide polymorphism (SNP), rs4722404, in the caspase recruitment domain family member 11 (CARD11) gene, which is associated with atopic dermatitis. Previous genetic studies have also reported genomic similarities between psoriasis and atopic dermatitis. However, little is known regarding the association between rs4722404 and psoriasis vulgaris (PsV). The aim of this study was to evaluate the relationship between rs4722404 and the risk and clinical features of PsV in a southern Chinese Han cohort. This hospital-based case-control study included 355 patients with PsV and 213 control subjects (N = 568); the samples were analyzed using a standard SNaPshot assay. We identified no association between the SNP and risk of PsV. However, a stratified analysis according to the age of onset, family history, and psoriasis area and severity index sub-phenotypes revealed a significant correlation between the C allele and CC+CT genotype of rs4722404 and an increased risk of early-onset PsV (≤40 years) compared to that of late-onset PsV (>40 years) (odds ratio, OR = 1.486; P = 0.026 for C allele and OR = 1.718, P = 0.023 for CC+CT genotype). The results of this study suggested that the SNP rs4722404 in CARD11 could increase the risk of early-onset PsV. Further studies must analyze the potential function of CARD11 in the pathogenesis of PsV.


Subject(s)
Asian People/genetics , CARD Signaling Adaptor Proteins/genetics , Guanylate Cyclase/genetics , Psoriasis/genetics , Adult , Alleles , CARD Signaling Adaptor Proteins/metabolism , Case-Control Studies , China , Cohort Studies , Dermatitis, Atopic/genetics , Ethnicity/genetics , Female , Gene Frequency , Genetic Predisposition to Disease , Guanylate Cyclase/metabolism , Humans , Male , Middle Aged , Polymorphism, Single Nucleotide
4.
Genet Mol Res ; 15(3)2016 Aug 19.
Article in English | MEDLINE | ID: mdl-27706581

ABSTRACT

Recent genetic evidence suggests a robust association of the CARD14 single nucleotide polymorphism rs11652075 (c.C2458T/p.Arg820Trp) and other rare mutations in this gene with psoriasis. To assess whether combined data support the relationship between CARD14 rs11652075 and susceptibility to this disease, we conducted a meta-analysis. PubMed (MEDLINE), EMBASE, Web of Science, and the Cochrane Library were searched for relevant papers published in English. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effect models. Heterogeneity between studies was assessed using the Cochran's Q and I2 statistics. A total of five published studies, including 32,807 psoriasis patients and 45,458 controls, met our inclusion criteria and were included in the meta-analysis. The pooled OR of the association between the minor allele of this polymorphism and psoriasis was 0.877 (95%CI = 0.834-0.922; P < 0.001). In a stratified analysis, pooled ORs relating to European and Asian ancestry were 0.883 (95%CI = 0.822-0.948) and 0.872 (95%CI = 0.812-0.936), respectively. Those calculated for studies with case sample sizes above and below 1000 were 0.912 (95%CI = 0.870- 0.956) and 0.824 (95%CI = 0.734-0.924), respectively. No publication bias was present, and the exclusion of any single dataset did not substantially alter the corresponding pooled ORs. Due to the limited data available regarding clinical classification of cases and genotypes, subgroup stratification by clinical type was not performed. Our results demonstrate a significant association between the CARD14 rs11652075 polymorphism and psoriasis.


Subject(s)
CARD Signaling Adaptor Proteins/genetics , Guanylate Cyclase/genetics , Membrane Proteins/genetics , Mutation, Missense , Psoriasis/genetics , Asian People/genetics , CARD Signaling Adaptor Proteins/metabolism , Case-Control Studies , Genetic Association Studies , Genetic Predisposition to Disease , Guanylate Cyclase/metabolism , Humans , Membrane Proteins/metabolism , Odds Ratio , Polymorphism, Single Nucleotide , Risk Factors , White People/genetics
5.
Allergy ; 70(12): 1605-12, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26310430

ABSTRACT

BACKGROUND: A cross-sectional retrospective study suggested a link between allergic diseases and Parkinson's disease. However, the temporal association between asthma and Parkinson's disease remains unknown. METHODS: From the Taiwan National Health Insurance Research Database, 10 455 patients who were diagnosed with asthma between 1998 and 2008 and aged ≥45 years and 41 820 age- and sex-matched controls were selected for our study and observed until the end of 2011. Those who developed Parkinson's disease during the follow-up period were identified. We also examined the asthma severity, as indicated by the frequency of admission (times per year) for asthma exacerbation, and the risk of subsequent Parkinson's disease. RESULTS: Patients with asthma had an increased risk of developing Parkinson's disease (hazard ratio [HR]: 3.10, 95% confidence interval [CI]: 2.20-4.36) after we adjusted for demographic data, health system use, medical comorbidities, and medication use. Sensitivity tests yielded consistent findings after we excluded observations on the first year (HR: 2.90, 95% CI: 2.04-4.13) and first 3 years (HR: 2.46, 95% CI: 1.64-3.69). Patients with asthma who had more frequent admissions (times per year) during the follow-up period exhibited a greater risk of subsequent Parkinson's disease (>2: HR: 16.42, 95% CI: 5.88-45.91; 1-2: 12.69, 95% CI: 5.03-31.71; 0-1: HR: 2.92, 95% CI: 1.91-4.49). CONCLUSION: Patients with asthma had an elevated risk of developing Parkinson's disease later in life, and we observed a dose-dependent relationship between greater asthma severity and a higher risk of subsequent Parkinson's disease.


Subject(s)
Asthma/epidemiology , Parkinson Disease/epidemiology , Aged , Comorbidity , Cross-Sectional Studies , Female , Humans , Longitudinal Studies , Male , Middle Aged , Proportional Hazards Models , Retrospective Studies , Risk Factors
6.
Nano Lett ; 13(12): 5797-802, 2013.
Article in English | MEDLINE | ID: mdl-24228733

ABSTRACT

The recent focus on topological insulators is due to the scientific interest in the new state of quantum matter as well as the technology potential for a new generation of THz optoelectronics, spintronics and quantum computations. It is important to elucidate the dynamics of the Dirac fermions in the topologically protected surface state. Hence we utilized a novel ultrafast optical pump mid-infrared probe to explore the dynamics of Dirac fermions near the Dirac point. The femtosecond snapshots of the relaxation process were revealed by the ultrafast optics. Specifically, the Dirac fermion-phonon coupling strength in the Dirac cone was found to increase from 0.08 to 0.19 while Dirac fermions were away from the Dirac point into higher energy states. Further, the energy-resolved transient reflectivity spectra disclosed the energy loss rate of Dirac fermions at room temperature was about 1 meV/ps. These results are crucial to the design of Dirac fermion devices.


Subject(s)
Nanostructures/chemistry , Nanotechnology , Optics and Photonics , Quantum Theory , Semiconductors , Spectrophotometry, Infrared
7.
Cytokine ; 56(3): 726-31, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21996013

ABSTRACT

Asthma is a chronic airway inflammatory disease. Chronic aspiration by gastric fluid in gastroesophageal reflux disease (GERD) is considered a primary inflammatory factor exacerbating or predisposing patients to asthma. Airway smooth muscle cells (SMCs) are considered an important component in airway remodeling. To investigate the role of gastric fluid in airway SMC inflammation and airway remodeling, we examined gastric fluid-induced cytokine and chemokine profiles, airway SMC migration and matrix metalloproteinase expression in rat primary rat airway SMCs. The T helper cell type 2 (Th2) cytokines interleukin 4, interleukin 6 and tumor necrosis factor 2 (TNF-α) and the chemokines, lipopolysaccharide-induced CXC chemokine (LIX/CXCL5), cytokine-induced neutrophil chemoattractant 2 (CINC-2), CINC-3, fractalkine, ciliary neurotrophic factor (CNTF), and vascular endothelial growth factor were induced by gastric fluid in primary cultured rat airway SMCs. Migration of rat airway SMCs was enhanced by gastric fluid and conditioned medium. The migration of rat airway SMCs enhanced by gastric fluid was associated with actin polymerization and activation of focal adhesion kinase. Matrix metalloproteinase 2 expressions in airway SMCs was enhanced by gastric fluid and conditioned medium. The results suggest potential mechanisms by which gastric fluid aspiration might influence SMC-mediated airway remodeling.


Subject(s)
Airway Remodeling , Body Fluids/metabolism , Chemokines/metabolism , Myocytes, Smooth Muscle/metabolism , Stomach/physiology , Trachea/cytology , Actins/metabolism , Animals , Cell Line , Cell Movement , Coculture Techniques , Enzyme Activation , Focal Adhesion Protein-Tyrosine Kinases/metabolism , Macrophages/cytology , Male , Matrix Metalloproteinase 2/metabolism , Mice , Myocytes, Smooth Muscle/cytology , Myocytes, Smooth Muscle/enzymology , Polymerization , Rats , Rats, Wistar
8.
Phys Rev Lett ; 104(3): 036103, 2010 Jan 22.
Article in English | MEDLINE | ID: mdl-20366662

ABSTRACT

We demonstrate the charge state of C60 on a Cu(111) surface can be made optimal, i.e., forming C60(3-) as required for superconductivity in bulk alkali-doped C60, purely through interface reconstruction rather than with foreign dopants. We link the origin of the C60(3-) charge state to a reconstructed interface with ordered (4x4) 7-atom vacancy holes in the surface. In contrast, C60 adsorbed on unreconstructed Cu(111) receives a much smaller amount of electrons. Our results illustrate a definitive interface effect that affects the electronic properties of molecule-electrode contact.

9.
Sci Adv ; 6(12): eaaz5015, 2020 Mar.
Article in English | MEDLINE | ID: mdl-32219169

ABSTRACT

The emergence of quantization at the nanoscale, the quantum size effect (QSE), allows flexible control of matter and is a rich source of advanced functionalities. A QSE-induced transition into an insulating phase in semimetallic nanofilms was predicted for bismuth a half-century ago and has regained new interest with regard to its surface states exhibiting nontrivial electronic topology. Here, we reveal an unexpected mechanism of the transition by high-resolution angle-resolved photoelectron spectroscopy combined with theoretical calculations. Anomalous evolution and degeneracy of quantized energy levels indicate that increased Coulomb repulsion from the surface states deforms a quantum confinement potential with decreasing thickness. The potential deformation strongly modulates spatial distributions of quantized wave functions, which leads to acceleration of the transition beyond the original QSE picture. This discovery establishes a complete picture of the long-discussed transition and highlights a new class of size effects dominating nanoscale transport in systems with metallic surface states.

10.
Eur Rev Med Pharmacol Sci ; 22(22): 7628-7632, 2018 11.
Article in English | MEDLINE | ID: mdl-30536303

ABSTRACT

OBJECTIVE: Retinoblastoma seriously threats to human health and life. Molecular targeted therapy of retinoblastoma supplies the direction of research in the future. This study aims to investigate the impact of DUSP1 on human retinoblastoma SO-Rb5 cell senescence. MATERIALS AND METHODS: Angiotensin II (AGII) was used to induce human retinoblastoma SO-Rb5 cell senescence model. DUSP1 over-expression plasmid and small interfere RNA (siRNA) were transfected into SO-Rb5 cells by Lipofectamine. Dual specificity phosphatase 1 (DUSP1), p53, p16, and protein kinase B (Akt) signaling expressions were detected with Western blot assay. SH-6 was applied to inhibit Akt signaling in SO-Rb5 cells. Cell senescence was evaluated by using ß-galactosidase test. RESULTS: DUSP1 level increased in SO-Rb5 cells induced by AGII. Senescence protein p53 and p16 significantly upregulated in SO-Rb5 cell senescence model, together with ß-galactosidase staining. DUSP1 plasmid transfection significantly enhanced DUSP expression, triggered SO-Rb5 cell senescence, and inhibited Akt signaling activation. DUSP1 siRNA exhibited the opposite effects. SH-6 significantly increased SO-Rb5 cell senescence induced by AGII through inhibiting Akt signaling. CONCLUSIONS: DUSP1 facilitated human retinoblastoma SO-Rb5 cell senescence induced by AGII through inhibiting Akt signaling pathway.


Subject(s)
Cellular Senescence/genetics , Dual Specificity Phosphatase 1/physiology , Oncogene Protein v-akt/genetics , Retinal Neoplasms/genetics , Retinal Neoplasms/pathology , Retinoblastoma/genetics , Retinoblastoma/pathology , Signal Transduction/genetics , Cell Line, Tumor , Dual Specificity Phosphatase 1/genetics , Genes, p16 , Genes, p53/genetics , Humans , RNA, Small Interfering/genetics , Up-Regulation/genetics
11.
Nat Commun ; 9(1): 1442, 2018 04 12.
Article in English | MEDLINE | ID: mdl-29650960

ABSTRACT

Because the surface-to-volume ratio of quasi-two-dimensional materials is extremely high, understanding their surface characteristics is crucial for practically controlling their intrinsic properties and fabricating p-type and n-type layered semiconductors. Van der Waals crystals are expected to have an inert surface because of the absence of dangling bonds. However, here we show that the surface of high-quality synthesized molybdenum disulfide (MoS2) is a major n-doping source. The surface electron concentration of MoS2 is nearly four orders of magnitude higher than that of its inner bulk. Substantial thickness-dependent conductivity in MoS2 nanoflakes was observed. The transfer length method suggested the current transport in MoS2 following a two-dimensional behavior rather than the conventional three-dimensional mode. Scanning tunneling microscopy and angle-resolved photoemission spectroscopy measurements confirmed the presence of surface electron accumulation in this layered material. Notably, the in situ-cleaved surface exhibited a nearly intrinsic state without electron accumulation.

12.
Sci Rep ; 7: 40886, 2017 01 20.
Article in English | MEDLINE | ID: mdl-28106144

ABSTRACT

X-ray scattering (XRS), x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopic techniques were used to study the electronic and atomic structures of the high-quality Sr3Ir4Sn13 (SIS) single crystal below and above the transition temperature (T* ≈ 147 K). The evolution of a series of modulated satellite peaks below the transition temperature in the XRS experiment indicated the formation of a possible charge density wave (CDW) in the (110) plane. The EXAFS phase derivative analysis supports the CDW-like formation by revealing different bond distances [Sn1(2)-Sn2] below and above T* in the (110) plane. XANES spectra at the Ir L3-edge and Sn K-edge demonstrated an increase (decrease) in the unoccupied (occupied) density of Ir 5d-derived states and a nearly constant density of Sn 5p-derived states at temperatures T < T* in the (110) plane. These observations clearly suggest that the Ir 5d-derived states are closely related to the anomalous resistivity transition. Accordingly, a close relationship exists between local electronic and atomic structures and the CDW-like phase in the SIS single crystal.

13.
Sci Rep ; 7(1): 161, 2017 03 13.
Article in English | MEDLINE | ID: mdl-28279015

ABSTRACT

The local electronic and atomic structures of the high-quality single crystal of SrFeO3-δ (δ~0.19) were studied using temperature-dependent x-ray absorption and valence-band photoemission spectroscopy (VB-PES) to investigate the origin of anisotropic resistivity in the ab-plane and along the c-axis close to the region of thermal hysteresis (near temperature for susceptibility maximum, Tm~78 K). All experiments herein were conducted during warming and cooling processes. The Fe L 3,2-edge X-ray linear dichroism results show that during cooling from room temperature to below the transition temperature, the unoccupied Fe 3d e g states remain in persistently out-of-plane 3d 3z2-r2 orbitals. In contrast, in the warming process below the transition temperature, they change from 3d 3z2-r2 to in-plane 3d x2-y2 orbitals. The nearest-neighbor (NN) Fe-O bond lengths also exhibit anisotropic behavior in the ab-plane and along the c-axis below Tm. The anisotropic NN Fe-O bond lengths and Debye-Waller factors stabilize the in-plane Fe 3d x2-y2 and out-of-plane 3d 3z2-r2 orbitals during warming and cooling, respectively. Additionally, a VB-PES study further confirms that a relative band gap opens at low temperature in both the ab-plane and along the c-axis, providing the clear evidence of the charge-density-wave nature of SrFeO3-δ (δ~0.19) single crystal.

14.
Sci Rep ; 6: 29288, 2016 07 18.
Article in English | MEDLINE | ID: mdl-27426677

ABSTRACT

In this study, we investigated a fluidic system that adheres to new concepts of energy production. To improve efficiency, cost, and ease of manufacture, a millimetrically scaled device that employs a droplet-based co-axial fluidic system was devised to complete alkali-catalyzed transesterification for biodiesel production. The large surface-to-volume ratio of the droplet-based system, and the internal circulation induced inside the moving droplets, significantly enhanced the reaction rate of immiscible liquids used here - soybean oil and methanol. This device also decreased the molar ratio between methanol and oil to near the stoichiometric coefficients of a balanced chemical equation, which enhanced the total biodiesel volume produced, and decreased the costs of purification and recovery of excess methanol. In this work, the droplet-based co-axial fluidic system performed better than other methods of continuous-flow production. We achieved an efficiency that is much greater than that of reported systems. This study demonstrated the high potential of droplet-based fluidic chips for energy production. The small energy consumption and low cost of the highly purified biodiesel transesterification system described conforms to the requirements of distributed energy (inexpensive production on a moderate scale) in the world.

15.
Biochim Biophys Acta ; 1309(1-2): 147-55, 1996 Nov 11.
Article in English | MEDLINE | ID: mdl-8950189

ABSTRACT

The single-stranded DNA binding protein from the filamentous bacteriophage cf has been purified and characterized. The first 12 amino acids, resulting from the N-terminal amino acid sequencing analysis of the protein, agree with an open reading frame (ORF) on the cf genome. The ORF contains 294 bp and codes for a 98 a.a. protein of molecular weight 10.8 kDa, consistent with the result from the denaturing protein gel analysis. The protein appears to be a homodimer as evident from the apparent molecular weight of about 22 kDa obtained from native protein gel analysis. The gene location of the protein has been identified as gene V of the cf single stranded genome, same as that from the M13 phage. The GVP of cf shows a strong sequence homology to the ssDNA binding proteins of Ff, IKe and Pf3 filamentous phages. The DNA binding wing of GVP, conserved among the filamentous phages, has been predicted for cf. To further characterize the protein, the GVP-ssDNA complex of cf has been purified from the infected host (Xanthomonas campestris pv. citri) by density gradient centrifugation. Transmission electron microscopy (TEM) images of the complex showed that it is about 1200 nm in length and 9 nm in diameter and it has a highly regular morphology with a central groove shadow running along the entire structure, but without any apparent helical pattern seen in the M13 complex. The GVP-ssDNA complex of cf seems more rigid than that of M13. Our computer modeling study suggested that this difference between the two complexes may be due to the additional 11 or 12 amino acids at the C-terminal end of the cf-GVP.


Subject(s)
Bacteriophages/metabolism , DNA, Viral/metabolism , DNA-Binding Proteins/metabolism , Amino Acid Sequence , Bacteriophages/genetics , Base Sequence , DNA, Single-Stranded/metabolism , DNA, Single-Stranded/ultrastructure , DNA, Viral/ultrastructure , DNA-Binding Proteins/chemistry , DNA-Binding Proteins/genetics , DNA-Binding Proteins/isolation & purification , DNA-Binding Proteins/ultrastructure , Genes, Viral/genetics , Molecular Sequence Data , Molecular Weight , Open Reading Frames/genetics , Restriction Mapping , Sequence Analysis , Sequence Homology, Amino Acid
16.
J Mol Biol ; 287(5): 867-76, 1999 Apr 16.
Article in English | MEDLINE | ID: mdl-10222197

ABSTRACT

Bacteriophage cf is the first single-stranded DNA phage that has been shown to set up a stable lysogenic state with its genome integrated into the host chromosome. From the isolation and characterization of a virulent mutant, cf-tv2, we report the first investigation into the mechanisms of the immunity established by the filamentous bacteriophage. The mutation in cf-tv2 enables the phage to produce plaques on lawns of cf lysogenic cells. The mutation was defined as a 49-nucleotide deletion located in a 0.59 kb NcoI/KpnI fragment of cf replicative form DNA. Two messages, cM1 and cM2, transcribed from the immunity region of wild-type cf but in opposite directions, were detected. In cf-tv2, the 49-nucleotide deletion abolishes cM2 transcription. The primer extension assay suggests a possible RNA-RNA interaction directed by base-pairing of the cM1 and cM2 RNAs. A frameshift mutation of the open reading frame ORF 165, encoded by cM2, resulted in a 10(5) plating efficiency on the cf lysogen. These observations suggest that both RNA-RNA interaction and repressor protein inhibition are involved in the mechanism of cf immunity. A model is proposed for the regulation of cf immunity.


Subject(s)
Bacteriophages/physiology , Bacteriophages/pathogenicity , Lysogeny/immunology , Amino Acid Sequence , Base Sequence , Cloning, Molecular , Molecular Sequence Data , Mutation , Open Reading Frames , RNA, Viral/genetics , RNA, Viral/metabolism , Repressor Proteins/genetics , Repressor Proteins/metabolism , Transcription, Genetic , Virulence/immunology
18.
Sci Rep ; 5: 10025, 2015 May 18.
Article in English | MEDLINE | ID: mdl-25985064

ABSTRACT

Graphene and its bilayer are two-dimensional systems predicted to show exciting many-body effects near the neutrality point. The ideal tool to investigate spectrum reconstruction effects is angle-resolved photoemission spectroscopy (ARPES) as it probes directly the band structure with information about both energy and momentum. Here we reveal, by studying undoped exfoliated bilayer graphene with ARPES, two essential aspects of its many-body physics: the electron-phonon scattering rate has an anisotropic k-dependence and the type of electronic liquid is non-Fermi liquid. The latter behavior is evident from an observed electron-electron scattering rate that scales linearly with energy from 100 meV to 600 meV and that is associated with the proximity of bilayer graphene to a two-dimensional quantum critical point of competing orders.

19.
J Endocrinol ; 147(1): 67-73, 1995 Oct.
Article in English | MEDLINE | ID: mdl-7490539

ABSTRACT

The combined effects of teleostean GH and human IGF-I in the regulation of teleost branchial cartilage growth were examined. Ceratobranchial cartilages were dissected from the common carp (Cyprinus carpio) and maintained in a defined culture medium supplemented with recombinant striped bass GH (sbGH), human IFG-I (hIGF-I) or both, and the uptake of [35S]sulphate by cartilage explants was measured. sbGH alone in the culture medium did not exhibit a significant stimulatory effect on the uptake of [35S]sulphate when compared with the controls. However, with hIGF-I in the culture medium, as low as 1 ng/ml, the stimulatory effect of sbGH was apparent and dose-dependent. The synergism of sbGH and hIGF-I was observed at the concentrations of 1 and 10 ng IGF-I/ml tested. At a constant hIGF-I concentration (10 ng/ml), a maximum stimulatory effect was detected with 3 micrograms recombinant sbGH/ml, at which point a 2.3-fold increase in sulphation activity was obtained when compared with the treatment with hIGF-I alone. A similar dose-dependent stimulatory effect was observed when native common carp and bonito GHs were tested using this assay system. These results suggest that the synergistic effect of sbGH and hIGF-I on sulphation activity is a common biological function of teleost GH, thus ruling out the possibility of experimental artifacts resulting from utilization of heterologous GH. Furthermore, experiments were conducted to test whether the synergism between sbGH and hIGF-I occurred between sbGH and insulin.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Cartilage/drug effects , Growth Hormone/pharmacology , Insulin-Like Growth Factor I/pharmacology , Sulfates/metabolism , Animals , Carps , Cartilage/growth & development , Cartilage/metabolism , Cattle , Dose-Response Relationship, Drug , Drug Synergism , Humans , Insulin/pharmacology , Stimulation, Chemical
20.
J Endocrinol ; 180(2): 247-55, 2004 Feb.
Article in English | MEDLINE | ID: mdl-14765976

ABSTRACT

The possibility that growth hormone (GH) has effects on long bone growth independent of insulin-like growth factor-I (IGF-I) has long been debated. If this is true, then long bone growth should be more profoundly affected by the absence of GH (since both GH and GH-stimulated IGF-I effects are absent) than by the absence of IGF-I alone (since GH is still present and actually elevated). To test this hypothesis, we compared long bone growth in mice with targeted deletions of Igf1 vs growth hormone receptor (Ghr). Tibial linear growth rate was reduced by approximately 35% in Igf1 null mice and by about 65% in Ghr null mice between postnatal days 20 and 40, a time of peak GH effect during normal longitudinal growth. The Igf1 null mouse growth plate demonstrated significant enlargement of the germinal zone; chondrocyte proliferation and numbers were normal but chondrocyte hypertrophy was significantly reduced. In contrast, the Ghr null mouse germinal zone was hypoplastic, chondrocyte proliferation and numbers were significantly reduced, and chondrocyte hypertrophy was also reduced. We have previously demonstrated that IGF-II is highly expressed in growth plate germinal and proliferative zones, so we considered the possibility that GH-stimulated IGF-II production might promote germinal zone expansion and maintain normal proliferation in the Igf1 null mouse growth plate. Supporting this view, IGF-II mRNA was increased in the Igf1 null mouse and decreased in the Ghr null mouse growth plate.Thus, in the complete absence of IGF-I but in the presence of elevated GH in the Igf1 null mouse, reduction in chondrocyte hypertrophy appears to be the major defect in longitudinal bone growth. In the complete absence of a GH effect in the Ghr null mouse, however, both chondrocyte generation and hypertrophy are compromised, leading to a compound deficit in long bone growth. These observations support dual roles for GH in promoting longitudinal bone growth: an IGF-I-independent role in growth plate chondrocyte generation and an IGF-I-dependent role in promoting chondrocyte hypertrophy. The question of whether GH has direct effects on chondrocyte generation is still not settled, however, since it now appears that IGF-II may medicate some of these effects on the growth plate.


Subject(s)
Bone Development/physiology , Growth Hormone/physiology , Insulin-Like Growth Factor I/metabolism , Receptors, Somatotropin/metabolism , Tibia/physiology , Animals , Chondrocytes/physiology , Gene Deletion , Growth Plate/cytology , Insulin-Like Growth Factor I/genetics , Insulin-Like Growth Factor II/genetics , Insulin-Like Growth Factor II/metabolism , Mice , Mice, Knockout , RNA, Messenger/analysis , Receptors, Somatotropin/genetics
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